Polyurethane Specifications.

Polyurethane is based on the polyaddition reaction between a polyol and a diisocyanate — an exothermic reaction. Polymerization is influenced by the type of polyol and isocyanate components as well as additives. Cell formation is obtained by adding a blowing agent (halogenated hydrocarbons with a low boiling point, or water, which reacts with isocyanate groups to form CO₂).

Density classes

Material class	Density	Typical uses
Solid PU elastomers	1,200 kg/m³	Print rollers, cast elastomers, RIM solid plastics
Microcellular foams & elastomers	800 kg/m³	Coatings, adhesives, sealants, elastomers
Low-density foams	from ~6 kg/m³	Footwear soles, integral-skin, bedding & upholstery, packaging
Rigid insulation foam (KPI)	30–55 kg/m³	Spray, panel and pour-in-place insulation

Thermal conductivity — rigid PU vs other insulation (equal performance thickness)

Insulation material	K-value W/m·°C	Thickness (mm)
Rigid polyurethane foam	0.019	34
Phenolic foam	0.037	42
Expanded polystyrene	0.040	48
Expanded cork	0.045	50
Fibre glass	0.045	40
Reinforced cement	0.050	90
Glass mineral wool	0.055	55
Foam glass	0.060	69

Thermal conductivity — rigid PU vs other insulation (equal performance thickness)

Insulation material	K-value W/m·°C	Thickness (mm)
Rigid polyurethane foam	0.019	34
Phenolic foam	0.037	42
Expanded polystyrene	0.040	48
Expanded cork	0.045	50
Fibre glass	0.045	40
Reinforced cement	0.050	90
Glass mineral wool	0.055	55
Foam glass	0.060	69